Many Internet portals provide a search engine with which a user may initiate an Internet search. The search engine returns a list of Web pages based upon a search expression received from the user.
Some search engines display a similarity value for each Web page in the list. Each similarity value numerically indicates a degree of correlation or relevance between its corresponding Web page and the search expression.
Oftentimes, the Web pages in the list are sorted based on the similarity values. By sorting the Web pages in this manner, the list presents highly-relevant Web pages before lesser-relevant Web pages.
Some Internet portals provide directories of Web pages. These directories provide a tree-like structure of categories and subcategories within which Web pages are classified.
DoubleClick, Inc. provides various Internet advertising solutions. These solutions include providing advertising for the ALTAVISTA™ Internet portal. Advertising on a search results page may be targeted based upon a keyword in a search expression submitted to the ALTAVISTA™ Internet portal.